Curtain hoist



Nov. 10, 1931. v. s. MCKENNY ET AL 8 CURTAIN HOIST Filed May 15, 1929 2 Sheets-Sheet 1 INVENTOR 5 Van 5. Me Kenn gamma R Crooke CZ ATTORNEY Nov. 10, 1931. v. s. MCKENNY-ET AL 1,331,123?

CURTAIN HOIST Filed May 13, 1929 '2 Sheets-Sheet 2 E gs INVENTORS I/an 5. Ma Ken/3y Roscoe R. Crooke Patented Nov. 10, 1931 UNITED STATES PATENT OFFICE VAN S. MCKENNY AND ROSCOE R. CROOKE, OF SEATTLE, WASHINGTON, ASSIGNORS TO THE PAGE MCKENNY COMPANY, OF SEATTLE, WASHINGTON, A CORPORATION 01 WASHINGTON CURTAIN HOIST Application filed May 13, 1929. Serial No. 362,622.

Our invention relates to improvements in electrically operated hoists for curtains of a type in general use on theatre stages and the like, and to the method of installing and operating the same.

Electricallyoperated curtain hoists of various kinds have been devised to facilitate the opening and closing of divided curtains for theatres whereby their operation could be controlled from the moving picture booth or from a convenient position on the stage, but such hoists heretofore have been expensive, heavy and cumbersome, and have required substantial and stationary means for mountin the hoist and an unsatisfactory system of cables for operating the curtains. These and other features have tended to limit their application to permanently located curtains.

The chief object of our invention is to provide a simple, compact, reliable and relatively light device of the kind described that is cheap to manufacture, easy to install and economical to operate.

Another object is toprovide an electrically operated curtain hoist adapted to operate either permanently located curtains, or ourtains mounted on battens that may be drawn up into, or lowered from, the scenery loft.

A further object is to provide a remotely controlled and electrically operated curtain hoist that will enable the operator to start, stop and reverse the curtain at any point in its travel while being opened or closed thus enhancing its usefulness for scenic effects and the like.

A still further and important object is to provide a curtain hoist of the kind described that will automatically stop the curtain at its extremity of opening and closing travel after the motor circuit is closed for either direction of operation.

A final object is to provide a hoist for the operation of divided curtains whereby slipping'of the operating cables is prevented and the permanent synchronizing of the movements of the two halves of the curtain is assured.

Other objects and advantages will be apparent from the following description of a preferred form of the invention clearly illustrated in the accompanying drawings, in which:

Figure 1 is a side elevation of a batten type curtain hoist embodying the invention with the cover of the limit switch box removed.

Fig. 2 is a top view of the same.

Fig. 3 is an elevation of the adjustable limit switch mechanism to an enlarged scale.

Fig. 4 is an elevation of a typical installation showing the rear side of the hoist and the method of mounting the same on the batten and the method of hanging and operating the curtain.

Fig. 5 is a diagram illustrating the system of cables, pulleys and counter-weight employed whereby the curtain and hoist may be raised and lowered as an integral unit.

Fig. 6 is a wiring diagram illustrating the electrical circuits employed for the control of the curtain hoist motor and the operation of the curtain.

Fig. 7 is a cross section of a common form of curtain truck and track.

Like reference numerals are used to indicate like parts throughout the drawings wherein a substantial iron casting 1, having machined surfaces 2 and 3 and downwardly projecting lugs 4, is the base member of the machine. A reducing gear housing casting 5 with machined surfaces 6, 6, 7 and 7 is fixedly attached to base 1 by means of cap screws 8.

In this way one of the open ends of housing 5 is closed by the machined end 3 of base 1, a gasket 9 of heavy paper, or the like, being used to make a tight joint and prevent the escape of oil or grease from the gear case. A U-shaped drum bracket member 10 having a machined surface 11 is fixedly attached to housing 5 by means of cap screws 12 and a second gasket 13 is used to make a tight joint between machined surfaces 7 and 11.

A drum 1 1 grooved as at 15 to receive the operating cable 16, is mounted between the arms of bracket 10 having sleeve bearings 17 preferably of bronze, on a shaft 18, fixedly attached to drum 1 1 by means of key 19, which is rotatably supported by said bearin s.

'lhe motive power for the operation of the device is supplied by a small reversible electric motor which is fixedly mounted on the finished surface 2 of base 1 by means of cap screws 22.

Mechanical energy is transmitted from shaft projection '23 of motor 20 by means of a flexible coupling 24 to worm shaft 25 rotatably mounted in bearings 26 and 26 carried by gear housing closure plates 27 and .27 which are secured to reduction gear housing 5 by means of cap screws 28, suitable gaskets 29 being used to make tight joints between.

machined surfaces 6 and 30 and surfaces 7 and 31. v

A double pitch, right hand worm is keyed to and rotates with worm shaft 25 and meshes with worm gear 33 removabl y secured to worm gear shattt 34 bymeans oita sunk key and set screw neither of which are shown. Shaft 34, rotatiyely mounted in bearings 35 which form :a part of the gear housing 5, has-ends projecting outsidethe bearings. On one of these projecting endsa suitable roller chain sprocket 86 is keyed in alignment with another and somewhat larger sprocket 37 which in turn is keyed to a projection 18' of shaft 18. A roller chain 38 is usedto connect the two sprockets as clearly illustrated in Figs'Q and 4 of the-d-rawirngs. Analuminum casting 39 removably secured in the position shown by means of cap screws 40, is used to enclose the drive chain and sprockets, as a guard against accidents. 7

It will be apparent from the-drawings and this specification, that the mechanical energy derived from the motor is transmitted y means of worm 32 and worm gear 33 to sprocket 36 at a reduced speed,=and the speed is further reduced by means of the sprocket and chain arrangement previously described. Hence mechanical energy from the motor is available for driving grooved drum 14 at the speed required for the proper operation of the curtains as hereinafter described.

In order to assurethestopping of the motor at either extremity of travel of the curtain, a limit switch 41 is employed to open the motor circuitthen'in use when the curtain has reached its limit of travel. This limit switch consists of a base of insulating material 42 which two electrically independent contact arms 43 and 43" having contacts 44 are pivotally mounted on terminail posts 45. Stetionzrry contact members 46 having contacts 47 and-terminal lugs 48 are fixedly secured to a raised portion 49 of base 42 by means of suitable machine screws 50, the arrangement being such that contacts 47 are adapted to engage contacts of contact arm's 43 and 43. These contacts are kept normally closed by means of a coiled'spring 51 whose looped ends engage "insulating sleeves 52 mounted on pins 53, projecting from contact arms '43" and 43. This limit switch assembly is removably secured to the-side wall of gear housing 5 in the position shown by means of machine screws 42.

The mechanism for actuating limit switch 41 is mounted above it on the same side wall of the gear housing by means of horizontal, parallel, rib-like projedions 56 and 58 cast integral with the housing. These rib-like projections have drilled holes for the reception of a rotatively mounted threaded shaft 59 and .a push rod 60, as clearly illustrated in Fig. 3 of the drawings. Thrust washers .61 and 62 coact with ribs 56 and 58, a shoulder projection 59 on shaft 59 and a small mitre gear 63, to maintain the shaft axially in position; the mitre gear being removabl secured to the shaft by a suitable taper pm 64. Stop members65 and 65 split on one s1de,are adapted to be adjustably clamped onto push rod 66 by means of machine screws A nut arm 67 threaded at 68, engaging the threads .59 of shaft 59 and having a -.cy fin- .dzrical aperture 69 sufficiently large to be readily slidable over rod 6.0,coacts with s members 65:1mdfi5 to operate this push: which, in turn, serves to operate the movable contact arms of limit switch 41 through the intermediney of a block of insulating material 70 secured to the lower end of the rod by ummnsof taper pin 71, which block of imsulating material engages one or the other of lugs v5T projecting outwardly from contact arms 43 and 48. The widthof the insulating bloekis madeless than the distance between these lugs, so that the tension of spring 51 is always effective in maintaining both pores of the limit switch'in :the closed position except when one or the other of the contact arms is actuated by the :push rod.

The operation-05f the limit switch mechanism is synchronized with that of drum 14 and operating cable 16, by means ofa second mitregear 63 which is mounted on a projection of worm gear shaft 34 and removuhly secured thereto by means of 1a. taper pin '64.

Thelimit switch and its operating mechanism are enclosed a sheet metal housing having a :body member 72 and a cover 73. The body member has inwardly projecting top and bottom flanges 72' and 72" respoc' tively, and is secured to gear housingifi by means of machine screws 74 which pass through'bottom flange 72". Flange 72 is drilled and tapped to reeeive'machinescrews 74 which'serve to removably secure cover 73 in position.

Squeeze connectors 7 5, passing through Ipertures in the side walls of housing 72, and bushings 76 are used to fixedly attach theends of flexible metal conduits 77 and 78 "to the limit switch housing, which also serves the purpose of a terminal and junction box for the electric wires 79, which are drawn into the conduits and serve to carry current to the motor. The motor terminals are enclosed in a suitable housing 80 which reends of wires 79 which connect with the wires of cable 82 inside the junction box in the usual way.

When mounted directly 011 the curtain batten 84 as illustrated in Figs. 4 and 5 of the drawings, the downwardly projecting lugs .4 of base casting 1 are made to straddle the batten, and bolts 85 passing through holes in the lugs and batten,.serve admirably to secure the hoist to the batten without disturbing the mechanism on the under side; and there is the further advantage of using the whole body of the bolts instead of the threads only to support the load, as is usually done. The-eye 86 in closure plate 27is at approximately the longitudinal center of gravity of the hoist, and advantage is taken of this to assist in hanging the curtain for raising and lowering, as illustrated in Fig, 5, wherein bridle cables 87 have their ends secured to the batten and their mid-points to counter weight cables 88 and 88'. It will be noted,

however, that the third bridle is dispensed with and that cable 88" has its end secured directly to the eye in the projecting end of closure plate 27. Cables 88, 88 and 88 pass oversheaves 89 and 89, and terminate at turn buckles 90 which are secured to a counterweight 91.. By adjustingthese turn buckles, the stresses may be equalized 1n the cables, and the curtain is easily raised and lowered by exerting a force in the proper direction in cable 92 which passes over top and bottom sheaves 93 in the usual way.

Any convenient method may be used to hang the curtain halves 94 and 94 so they may be opened and closed by means of the curtain hoist of our invention. In the drawings, the curtain halves are shown supported by means of a sheet metal track section 95, secured to the under side of batten 84 by means of screws 96. Small curtain trucks 97 comprised of body members 98 having downwardly projecting eyes 98 and horizonvtally projecting axles 98" on which fibre rollers 99 are revolubly mounted, are used to support the curtain halves at frequent These truck members are adapted to fit within track section 95 with their axles transverse of the longitudinal axis of the track so rollers 99 will be supported by the inwardly projecting track flanges 95 on which they are free to roll back and forth for the full length of the batten. The curtain is removably fastened to the eyes 98 of trucks 97 by means of clasps 100 which are aflixed to the curtain by means of stout straddle strips 101 securely sewed to the curtain. Two of the curtain trucks of each half of the curtain have their eyes secures to a longitudinally disposed metal strap 102 provided with spaced holes 102 into which the last two curtain clasps at the inner edge of the curtain are fastened.

The curtains are operated by the curtain hoist through the intermediacy of the flexible metal cable 16-one end of which is carried over around drum 14 and passed through a hole 104 where it is tied into a knot thus anchoring that end securely to the drum. The cable then passes over idler sheave 105 which is free to revolve on, and slide axially along idler shaft 106 held stationary in apertures in the ends of arms 10 by means of shoulders abutting the inner faces of the arms and nuts 108 secured against loosening by means of spring washers 109. From this idler sheave the cable passes down over one of a pair of sheaves 110 revolubly mounted in a suitable frame 111 affixed to one end of batten 84, thence under the batten on the near side of the curtain to the far end of the batten where it passes around a horizontally mounted sheave 112 and returns on the far side of the curtain to the hoist end of the batten where it passes up over a second sheave 110 and under idler sheave 105 to drum 14 where a sufiicient length is wound around in grooves 15 to more than equal the extreme travel distance of one of the curtain halves,

and is then passed through a second hole 113 and the cable on the far side of the bat ten is secured to strap 102' of curtain half 94 by means of a similar U-bolt clamp.

Motor 20 should have a normal rating of about horse power and is preferably of the commutator and double-field-winding type, whether operated by direct or alternating current. Such a motor is represented diagrammatically in Fig. 6 of the drawings, wherein 114 is the armature member which is permanently connected to two independent field windings 115 and 115 wound in opposite directions on the same field poles. It is obvious to one skilled in the art that the motor will operate in onedirection when current passes through the armature and field winding 115, and in the opposite direction when it passes through the armature and field winding 115.

It is customary to provide at least two control stations for the operation of the curlhOiSt. One .ofthese 116 is usually in the moving picture booth :the other 117 is .at'the electricianls station on the stage. The wirdiagram shown is therefore for twostation control, aith'ou'gh it is obvious that the wiring system maybe adapted to provide control from any "number of stations.

-2Curre11t :from the source of electricity is married ."to the first control station 116 by means of conductors 118. Conductors 119 areausedzto connect stations E116 and 117 elec- :trica'lly and conductors 79 in turn connect station 117 with the hoist motor .20 through limit switch contact arms 43 and 43. Switches 121, 122 and .122 are of the three wvaytype and switch 121 is of the four-way The two corresponding positions for the left switchzof each station are mar-ked'Start and Stop respectively, and those for the switches at the right at each station are marked ()pen and Close, respectively. The curtain is considered to be in its normal position when closed and the switches in their -normal tpositions when as indicated in the diagram.

To open the curtain halves the operator say tit-station 1 16, simply moves switch 122 to the start position which closes the circuit between the source, armature 114 and field winding 115' as will be seen 'by tracing the new circuit thus provided. This causes armature 114.- to rotate in a counter-clockwise direction when facing the commutator end of the motor and through the intermediacy of the reducing gear and chain drive, hereinbeforedescribed, drum 14 is likewise rotated in a clockwise direction, as indicated in Fig. 4, which unwinds cable 16 from the far side of said drum and simultaneously winds the same onto the near side of the drum, thus imparting motion to the cable in the directions indicated by arrows in the drawings. Strap 102 is thereby drawn to the left and strap 102" is simultaneously drawn to the right, thus pushing back curtain trucks 9'7 alongtrack 95 and folding the curtain in the usual way.

After the curtain has opened a short distance, the nut arm 67 of limit switch 41 will have been lowered by the turning threaded shaft '59 sufiiciently to close switch 43 thus completing both field circuits between the motor windings and control station 117.

It is apparent from the diagram that the curtain may then be stopped, started, opened or closed by throwingthe switches of control station 116 to the positions indicating the operation desired, or if the curtain is to be fully opened after the switch previously mentioned has been thrown to the start posi tion, the operator need'not give the curtain any further attention, for the downward movement of limit switch nut arm 67 will engage stop and force push rod GO-downmotor through switch 43 and field winding 115, reversing the direction of rotation oi the motor .and closing the curtain; otherwia switch 122 is thrown to the stop position and switch 121'is then thrown to the clnm position. The curtain may then be clnsed by simply throwing switch 122 to the start position.

When the curtain is fully closed switchefl will be opened automatically by the limit switch mechanism thus stopping the motor. Switch 122 should then be thrown to the stop position. With the switches in the position shown, the curtain may be controlled from station 117 in precisely the "smme'way as previously described for the control of the curtain from station 116.

l Vhile'the position of theswitches as described is desirable for the sake of simplicity and the avoidance of confusion'where twoor more control stations are employed, it'is apparent to one skilled in the art that the curtain may be fully controlled at any timef-rom any one of the control stations. For instance, the stage electrician will at all times have full control of the curtain from station 117 and can open and close the curtain in case of emergency irrespective ofthe setting 01 the switches at station 116.

Where the curtain is not to be raised and lowered it is unnecessary to mountthe hoist on the curtain batten as herein illustrated and, in fact, that method of mounting is somewhat objectionable "on account of the additional head room required and the inaccessibility of the mechanism. It is customary in such cases to mount the hoist in the usual way 011 a suitable length of curtain batten which in turn is bolted to the stage floor opposite the end of the curtain, and idler sheaves and 105 are transferred from idler shaft 106 to idler shaft 106' as shown in Fig. 1.

Sheaves are so mounted that cable 16 horizontally disposed on either side of the curtain may pass over them and down to idler sheaves 105 and 105' and thence about cable drum 14 where the ends are secured as previously described.

When the hoist is mounted in this manner border cable 82 and junction box 83 are omitted, thus materially reducing the cost of the installation. The operation of the device thus installed is precisely the same as previously described.

It will be obvious that this device may be adapted to the raising and lowering of curtains as well as to the drawing of curtains of the type described.

The foregoing description in connection with the accompanying drawings, the plan of no construction and method of operation of our invention will be readily apparent but, while we have disclosed what we now consider to be the preferred embodiment of the invention, it will be understood that many changes may be made in the details of construction and adaptation of the device without departing from the purpose and intent of the invention within the scope of the following claims.

We claim:

1. Curtain means of the class described, embodying a vertically movable batten, curtains suspended from said batten for sidewise movement, power operated winding drum means mounted on said batten, and cables interconnecting said winding drum means and said curtains whereby the curtains may be opened and closed by the winding drum means.

2. Curtain means of the class described, embodying a vertically movable batten, curtains suspended from said batten for sidewise movement, electrically operated winding drum devices carried on said batten for moving said curtains, and means operable from a remote point for controlling said electrically operated devices.

3. Curtain means of the class described, embodying a vertically movable batten, curtains suspended from said batten for sidewise movement, electrically operated winding drum devices carried on said batten for opening and closing said curtains, and control means operable from a remote point for starting and stopping said electrically operated, winding drum devices to move said curtains into any desired position between the fully closed and the fully open positions.

4. The apparatus as claimed in claim 3 in which automatic means are provided for stopping said electrically operated devices when the curtains reach a fully open or a fully closed position.

5. Curtain means of the class described, embodying a vertically movable batten, two curtains supported from said batten and arranged to be drawn sidewise into an open or a closed position, cables connected with said curtains near their upper ends for drawing the same, a winding drum mounted on said batten and having the two ends of said cable drawn in opposite directions about said drum and rigidly secured thereto whereby slippage of said cable will be prevented and one end of said cable will be wound onto said drum as the other end is unwound therefrom and means for driving said winding drum.

6. Curtain means of the class described, embodying a vertically movable batten, two curtains, roller means suspending said two curtains from said batten leaving said ourtains free to be closed and opened by drawing said curtains sidewise toward and away from each other, a cable connected with the upper ends of said curtains near the edges of the curtains which are brought together when the curtains are closed, means for guiding said cable, a winding drum mounted on said batten and having the two ends of said cable drawn in'opposite directions around said drum and rigidly secured thereto, Whereby one end of said cable will be wound onto said drum as the other end is unwound therefrom, and means for driving said winding drum to move said curtains in opposite directions between a fully closed and a fully open position.

7 The apparatus as claimed in claim 6 in which the winding drum is provided with means for securely fastening the ends of the cable to said drum.

8. Devices of the class described embodying a curtain suspended for drawing movement between an open and a closed position, power operated winding drum means for drawing said curtain, manually governed control devices for stopping said power operated means for any position of the curtain, and automatic means actuated by saidpower winding drum mechanism and independent of said control for stopping said power operated means when the curtain reaches a fully open or a fully closed position.

9. Devices of the class described embodycurtains suspended vertically and arranged to be drawn between open and closed positions, electrically operated winding drum means for moving said curtains, control devices for selectively stopping, starting or reversing said electrically operated means for any position of the curtain.

10. Curtain operating devices of the class described embodying a frame, a motor mounted on said frame,a winding drum mounted in the frame, cables on and secured to said drum for opening and closing curtains, drivin means interconnecting said motor and sai drum and a limit switch connected with said driving means for breaking the circuit to said motor after a predetermined number of revolutions of said drum in either direction.

11. Curtain operating devices of the class described embodying a frame, a reversible motor mounted on said frame, a winding drum mounted in the frame, curtain operating cables on and secured to said winding drum, driving means interconnecting said motor and said winding drum, and an automatic switch operated by said motor and controlling the circuit to said motor and limiting the operation of said motor in both directions.

12. The apparatus as claimed in claim 11 in which manually operated switch means are provided at a remote point in the circuit in eluding said automatic switch for starting and stopping said motor at will.

13. Curtain operating devices of the class describedembodying a frame, a reversible motor on said frame, a: winding drum onsaid frame,curtain operating cables Wound inv opposite directions on and securedto said winding drum, a gear housingbetween said motor andasaid winding drum, aztransverseshaft extending through said gear housing, worm gear means connecting said transverse" shaft with said motor, link belt means forming a driving connection between said transverse shaft andsaid winding drum, a switch housing at one side'of said gear housing, and limit switchmeans in said housing. and controlling the circuit to said motor and driven from said transverse shaft.

14. Curtain o erating devices of the class described embo ying a frame, a reversiblemotor on said frame, a winding drum. on said frame, curtain operating cables. wound in opposi te directions on and secured to said winding' drum, a. gear housingbetween said motor and said windingdrum, a transverse shaft extending through said gear housing, worm gear means connecting said transverse shaft with said motor, link belt means forming a driving connection between said transverse shaft and said winding, drum, a switch housing at one side of said gear housing, a screw shaft in said switch housing, gear means for driving said screw shaft from said transverse shaft, a switch operating member threaded onto said screw shaft, and a switch control-' ling-the circuits to said motor and arrangedto be opened when said switch operating member reaches a predetermined position in its movement in either direction on said screw shaft.

15. Curtain means of the class described, embodyingavertically movable batten, curtains. supported from said batten and arranged to be drawn sidewise into an open or a closed position, cables connected withsaid curtains near their upper endsfor drawing the same,va winding drum. mounted on said batten, the two ends of said cable being wound in opposite directions about said windingd'rum; and rigidly secured thereto whereby slippage of said cable will be prevented, andwhereby one end of said cable will. be Wound onto said drum as theother end is unwound therefrom, a reversible motor of1the commutator and double field winding type for driving said drum and circuit meansicontrolling the operation of said motor;

The foregoing specification signed at Seatt1'e,Wash.,rl\Iay 3, 1929.

VAN S. MGKENNY. BOSCOE R. CROO'KE. 

